Golf club head with high-density heel and toe weight and method of making same

ABSTRACT

A method of forming a golf club head includes providing a body having an end portion (e.g., a heel end or a toe end of the club head) wherein the body end portion includes a lower surface and a boss extending therefrom. The method comprises providing a weight having a top surface and a cavity configured to receive the boss, and inserting the boss on the body into the cavity in the weight by rotating the weight such that the boss interlocks with the cavity and so that at least a portion of the top surface of the weight contacts at least a portion of the lower surface of the body end portion. The weight further includes a protrusion having a concave surface and the body has a corresponding convex surface. The weight is rotated about an axis extending through the body such that the concave surface of the weight bears on the convex surface of the body

BACKGROUND OF THE INVENTION

This invention relates generally to golf clubs and, in particular, to a method for fabricating a golf club head having heel and toe weights.

It is often desirable to incorporate heel and toe weighting into a club head body to increase the moment of inertia of the club. This increased moment of inertia tends to decrease club head twisting in the event the golfer strikes the golf ball off-center. In an effort to increase the moment of inertia, some prior art club heads utilize a low-density material for the club head body in conjunction with a higher density material for the heel and toe weights.

The use of perimeter weighting can lead to a number of manufacturing problems, however. For example, it is often difficult to join the perimeter weights to the club head body such that the weights are securely attached to the body.

Furthermore, in cases where variable or customization of weighting is desired, known perimeter weighting techniques make it difficult or impossible to change weighting schemes. This is particularly the case where the perimeter weights and club head body are fabricated using different materials which may not be amenable to the same processing techniques and whose different mechanical characteristics make them difficult to join in a robust manner.

SUMMARY OF THE INVENTION

The present invention provides a golf club head having a body fitted with heel and toe weights attached in an advantageous manner. In accordance with one embodiment of the present invention, a method of forming a golf club head includes providing a body having an end portion (e.g., a heel or a toe end of the club head) wherein the body end portion includes a lower surface and a boss extending therefrom. The method comprises providing a weight having a top surface and a cavity configured to receive the boss and inserting the boss on the body into the cavity in the weight by rotating the weight such that the boss interlocks with the cavity and so that at least a portion of the top surface of the weight contacts at least a portion of the lower surface of the body end portion.

In accordance with one embodiment, the weight further includes a protrusion having a concave surface and the body has a corresponding convex surface. The weight is rotated about an axis extending through the body such that the concave surface of the weight bears on the convex surface of the body.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective overview of an end portion of a golf club head including a body that is interlocked with a weight;

FIG. 2A is a rear elevational view of the club head end portion shown in FIG. 1 before interlocking the body and the weight;

FIG. 2B is anointer rear elevational view of the club head end portion shown in FIG. 1 with the body and the weight partially interlocked; and

FIG. 2C is a further rear elevational view of the club head end portion shown in FIG. 1 with the body and the weight fully interlocked.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates an end portion (e.g., a heel end or a toe end) of a golf club head 100, preferably a putter head, including an interlocking body 102 and a weight 104 in accordance with one embodiment of the present invention. As shown, body 102 includes a boss 106 generally configured to interlock with a corresponding cavity 108 within weight (or “ballast”) 104. More particularly, boss 106 includes two generally arcuate surfaces 110 and 112 which mate with corresponding arcuate surfaces 120 and 122 within cavity 108 of weight 104, while two generally planar surfaces 116 and 114 on opposite sides of boss 106 mate with corresponding planar surfaces 126 and 124 of cavity 108. Hence, it is preferred that the radius of curvature of surfaces 110, 112, 108, and 122 are substantially identical (and their centers of rotation coincident) to facilitate the rotation of weight 104 as boss 106 seats within cavity 108. As is known in the art, an exemplary golf putter club head typically includes a body having a front (“striking”) face, a bottom surface or “sole”, a heel region, and an opposite toe region. The body 102 is typically attached to a shaft (not shown) via a suitable hosel (not shown).

FIGS. 2A-2C progressively show the insertion of boss 106 within cavity 108 during fabrication of an exemplary putter head. Initially, as shown in FIGS. 1 and 2A, weight 104 is separate from body 102. Weight 104 preferably includes an end protrusion 130 having a concave surface 204 which is generally configured to rotate about and contact a convex bearing surface 202 on body 102. Body 102 includes a bottom surface 212 and weight 104 includes a top surface 210. Boss 106 extends outward from bottom surface 212 of body 102.

As shown in FIG. 2B, weight 104 is positioned such that boss 106 is aligned with and is poised to enter cavity 108, while concave surface 204 is placed in contact with convex surface 202 of body 102. Thus, surface 202 provides a point of leverage that assists with rotation of weight 104 into engagement with boss 106. Weight 104 is then further rotated about an axis 205 extending through body 102, which also generally corresponds to the center of curvature of the mating arcuate surfaces of weight 104 and body 102 (e.g., surfaces 110, 112, 120, and 122 shown in FIG. 1). Weight 104 is rotated until it suitably interlocks with body 102, e.g., until surface 210 of weight 104 at least partially contacts surface 212 of body 102.

In this regard, weight 104 may be secured to body 104 in any convenient fashion. In the illustrated embodiment, for example, weight 104 is secured using a machine screw 250. Any other suitable method may be used, however, including various adhesives, rivets, pins, interference fit, soldering, brazing, and/or the like.

In the illustrated embodiment, weight 104 constitutes a portion of one or more active surfaces of the assembled club head. For example, referring to FIGS. 1, 2A-2C, club head body 102 will typically include a front surface 142. Weight 104 then preferably includes a corresponding front surface 140 which, in the assembled state, is preferably flush with the front surface 142 of body 102 thereby forming a striking face on the club head. Similarly, referring to FIG. 2C, a bottom surface 260 of weight 104 may be configured such that it forms a portion of the sole 262 of club head body 102.

Body 102 and weight (or weights) 104 comprise any suitable metal, plastic, composite material, or combination thereof. In accordance with one embodiment, body 102 comprises a material such as titanium or a high-purity titanium alloy, e.g., commercial pure grade 2 titanium, and weight 104 comprises a material whose density is greater than that of body 102—e.g., tungsten. While body 102 and weight 104 may be fabricated from a metallic material, the present invention is not so limited. For example, the primary constituent of body 102 might include a composite or plastic material having the desired characteristics.

Depending upon the selected material or materials, body 102 may be fabricated using any suitable process now known or later developed, including a variety of conventional casting methods such as investment-casting, powdered-metal processing, and/or metal machining. In one embodiment, body 102 is formed via a suitable casting process and the assembled unit (with heel and toe weights) is thereafter milled to finish the various exposed surfaces.

The shape and materials used for body 102 and weight 104 is defined by any suitable factors, including, for example, club head type, desired moment of inertia (e.g., the polar moment of inertia around an axis normal to the club head sole), desired center of gravity, desired aesthetic properties (e.g., visual cues provided by the club head's contours as viewed from above during play), and/or the desired weight, mass, and density. In this regard, it will be appreciated that the exemplary club head shapes depicted in FIGS. 1 and 2 are for illustrative purposes only, and that the present invention is not so limited.

It will be appreciated that two weights 104 of equal mass having a density greater than that of the body 102 may be used in both the heel and toe ends of the club head. This weight placement, toward the antipodal extremes of the toe and heel ends, increases the moment of inertia of the club head while at the same time keeping the weight low and close to bottom surface 262 (thus lowering the center of mass and facilitating desirable spin characteristics upon impact).

The particular shape of boss 106 and cavity 108 as illustrated are not meant to limit the scope of the present invention. For example, while boss 106 is shown as a type of solid-of-revolution based on a square or rectangular cross-section, boss 106 may have any suitable shape and cross-section (e.g., circular, oval, curvilinear, rectilinear, or a combination thereof). Boss 106 may also be tapered or have another suitably varying cross-section.

Boss 106 may terminate within weight 104 (e.g., at approximately half of the thickness of weight 104, as shown in FIG. 2C), or may extend entirely through weight 104 such that it forms a part of sole 262 of body 102.

Although the invention has been described herein in conjunction with the appended drawings, those skilled in the art will appreciate that the scope of the invention is not so limited. For example, while the present invention has been described in terms of golf putters, many other types of golf clubs would profit from the present invention, including irons, metal woods, etc. Moreover, while titanium and tungsten have been cited as preferred materials for the body and inserts respectively, it will be appreciated that any suitable material now known or later developed may be used in connection with the present invention, including various metals, alloys, composites, ceramics, and the like. These and other modifications in the selection, design, and arrangement of the various components and steps discussed herein may be made without departing from the scope of the invention as set forth in the appended claims. 

1. A method of forming a golf club head, said method comprising: providing a body having an end portion, wherein said body end portion includes a lower surface and a boss extending therefrom; providing a weight having a top surface and a cavity configured to receive said boss; and inserting said boss into said cavity by rotating said weight such that said boss interlocks with said cavity and so that at least a portion of said top surface of said weight contacts at least a portion of said lower surface of said body end portion.
 2. The method of claim 1, further including securing said weight to said body end portion.
 3. The method of claim 2, wherein said securing step includes fastening said weight to said body using a screw inserted through said weight into said body.
 4. The method of claim 1, wherein said weight further includes a protrusion having a concave surface and wherein said body has a corresponding convex surface, and said rotating step including rotating said weight about an axis extending through said body such that said concave surface of said weight bears on said convex surface of said body.
 5. The method of claim 1, wherein said end portion of said body corresponds to a heel end of said body.
 6. The method of claim 1, wherein said end portion of said body corresponds to a toe end of said body.
 7. The method of claim 1, wherein said body includes another end portion, and wherein said method further includes providing another weight configured to interlock with said another end of said body.
 8. The method of claim 1, wherein said body and said weight each include a front surface, and wherein said rotating step includes rotating said weight such that said front surface of said weight is substantially flush with said front surface of said body thereby forming a striking face on said golf club head.
 9. The method of claim 1, wherein said body includes a sole, said weight includes a bottom surface, and wherein said rotating step includes rotating said weight such that said bottom surface of said weight is substantially flush with said sole.
 10. A golf club head comprising: a body having an end portion, said body end portion including a lower surface and a boss extending therefrom; and a weight having a top surface and a cavity configured to receive said boss, said boss being rotatably inserted into said cavity such that said boss interlocks with said cavity and so that at least a portion of said top surface of said weight contacts at least a portion of said lower surface of said body end portion.
 11. The club head of claim 10, wherein said weight is secured to said body end portion.
 12. The club head of claim 11, wherein said weight is fastened to said body using a screw inserted through said weight into said body.
 13. The club head of claim 10, wherein said weight further includes a protrusion having a concave surface and wherein said body has a corresponding convex surface.
 14. The club head of claim 10, wherein said body end portion corresponds to the heel of said body.
 15. The club head of claim 10, wherein said body end portion corresponds to a toe end of said body.
 16. The club head of claim 10, wherein said body and said weight each include a front surface, and wherein said front surface of said weight is substantially flush with said front surface of said body in order to form a striking face on said club head.
 17. The club head of claim 10, wherein said body includes a sole, said weight includes a bottom surface, and wherein said bottom surface of said weight is substantially flush with said sole.
 18. The club head of claim 10, wherein said body comprises a material having a density greater than that of said weight.
 19. The club head of claim 18, wherein said body comprises titanium and said weight comprises tungsten. 